// 转换为数字 
function intval(v) 
{ 
   v = parseInt(v); 
   return isNaN(v) ? 0 : v; 
} 
 
// 获取元素信息 
function getPos(e) 
{ 
   var l = 0; 
   var t  = 0; 
   var w = intval(e.style.width); 
   var h = intval(e.style.height); 
   var wb = e.offsetWidth; 
   var hb = e.offsetHeight; 
   while (e.offsetParent){ 
       l += e.offsetLeft + (e.currentStyle?intval(e.currentStyle.borderLeftWidth):0); 
       t += e.offsetTop  + (e.currentStyle?intval(e.currentStyle.borderTopWidth):0); 
       e = e.offsetParent; 
   } 
   l += e.offsetLeft + (e.currentStyle?intval(e.currentStyle.borderLeftWidth):0); 
   t  += e.offsetTop  + (e.currentStyle?intval(e.currentStyle.borderTopWidth):0); 
   return {x:l, y:t, w:w, h:h, wb:wb, hb:hb}; 
} 
 
// 获取滚动条信息 
function getScroll()  
{ 
   var t, l, w, h; 
    
   if (document.documentElement && document.documentElement.scrollTop) { 
       t = document.documentElement.scrollTop; 
       l = document.documentElement.scrollLeft; 
       w = document.documentElement.scrollWidth; 
       h = document.documentElement.scrollHeight; 
   } else if (document.body) { 
       t = document.body.scrollTop; 
       l = document.body.scrollLeft; 
       w = document.body.scrollWidth; 
       h = document.body.scrollHeight; 
   } 
   return { t: t, l: l, w: w, h: h }; 
} 
 
// 锚点(Anchor)间平滑跳转 www.zzarea.com
function scroller(el, duration) 
{ 
   if(typeof el != 'object') { el = document.getElementById(el); } 
 
   if(!el) return; 
 
   var z = this; 
   z.el = el; 
   z.p = getPos(el); 
   z.s = getScroll(); 
   z.clear = function(){window.clearInterval(z.timer);z.timer=null}; 
   z.t=(new Date).getTime(); 
 
   z.step = function(){ 
       var t = (new Date).getTime(); 
       var p = (t - z.t) / duration; 
       if (t >= duration + z.t) { 
           z.clear(); 
           window.setTimeout(function(){z.scroll(z.p.y, z.p.x)},13); 
       } else { 
           st = ((-Math.cos(p*Math.PI)/2) + 0.5) * (z.p.y-z.s.t) + z.s.t; 
           sl = ((-Math.cos(p*Math.PI)/2) + 0.5) * (z.p.x-z.s.l) + z.s.l; 
           z.scroll(st, sl); 
       } 
   }; 
   z.scroll = function (t, l){window.scrollTo(l, t)}; 
   z.timer = window.setInterval(function(){z.step();},13); 
} 